The Third Ephorate of Ancient Antiquities is an archaeological authority responsible for preserving, managing, and studying antiquities and cultural heritage in a specific region or area in Greece.

The Euphrates is named after the ancient Greek institution of the ephors, who were magistrates responsible for various administrative and judicial duties in ancient Sparta. In modern Greece, the regional authorities responsible for archaeological research and conservation are separated.

The Third Ephorate of Ancient Antiquities is based in the city of Thessaloniki and is responsible for the management of archaeological sites and monuments in the regions of Central Macedonia and Eastern Macedonia, and Thrace. Some of the notable archaeological sites and monuments under its jurisdiction include the ancient cities of Dion and Philippi, the Roman Forum and Rotunda in Thessaloniki, and the archaeological site of Vergina, which was the capital of the ancient kingdom of Macedon and the burial site of the kings of Macedon, including Alexander the Great's father, Philip II.

The Third Ephorate of Ancient Antiquities plays a crucial role in the preservation and study of Greece's rich cultural heritage and history. Its responsibilities include conducting archaeological excavations, managing archaeological sites and monuments, preserving and restoring artefacts and monuments, conducting research and documentation, and promoting public awareness and education about Greece's ancient past.